Abstract This is a review of gas cleaning methods to be used for particulate removal from the gas... more Abstract This is a review of gas cleaning methods to be used for particulate removal from the gases emerging from pressurized coal gasifiers or fluid bed combustors at high temperature and high pressure. References are given (collected in tables) for the emissions of these processes, the inlet requirements if the hot gas is to pass a turbine and all cleaning methods that have been proposed in this context, including the removal of gaseous alkalis. The design feasibility and available performance data for high temperature, high pressure applications of cyclones, electrostatic precipitators, barrier filters (using fibre, felt and sintered filter elements) and various types of granular bed filters, are discussed in some detail and suggestions are made for the further research and development. The theory of capture mechanisms is reviewed in so far as relevant in the present context. Turbulent flow, electrostatic forces, and re-entrainment are the phenomena that require special attention in almost all applications.
Abstract This is a review of gas cleaning methods to be used for particulate removal from the gas... more Abstract This is a review of gas cleaning methods to be used for particulate removal from the gases emerging from pressurized coal gasifiers or fluid bed combustors at high temperature and high pressure. References are given (collected in tables) for the emissions of these processes, the inlet requirements if the hot gas is to pass a turbine and all cleaning methods that have been proposed in this context, including the removal of gaseous alkalis. The design feasibility and available performance data for high temperature, high pressure applications of cyclones, electrostatic precipitators, barrier filters (using fibre, felt and sintered filter elements) and various types of granular bed filters, are discussed in some detail and suggestions are made for the further research and development. The theory of capture mechanisms is reviewed in so far as relevant in the present context. Turbulent flow, electrostatic forces, and re-entrainment are the phenomena that require special attention in almost all applications.
Abstract This is a review of gas cleaning methods to be used for particulate removal from the gas... more Abstract This is a review of gas cleaning methods to be used for particulate removal from the gases emerging from pressurized coal gasifiers or fluid bed combustors at high temperature and high pressure. References are given (collected in tables) for the emissions of these processes, the inlet requirements if the hot gas is to pass a turbine and all cleaning methods that have been proposed in this context, including the removal of gaseous alkalis. The design feasibility and available performance data for high temperature, high pressure applications of cyclones, electrostatic precipitators, barrier filters (using fibre, felt and sintered filter elements) and various types of granular bed filters, are discussed in some detail and suggestions are made for the further research and development. The theory of capture mechanisms is reviewed in so far as relevant in the present context. Turbulent flow, electrostatic forces, and re-entrainment are the phenomena that require special attention in almost all applications.
Abstract This is a review of gas cleaning methods to be used for particulate removal from the gas... more Abstract This is a review of gas cleaning methods to be used for particulate removal from the gases emerging from pressurized coal gasifiers or fluid bed combustors at high temperature and high pressure. References are given (collected in tables) for the emissions of these processes, the inlet requirements if the hot gas is to pass a turbine and all cleaning methods that have been proposed in this context, including the removal of gaseous alkalis. The design feasibility and available performance data for high temperature, high pressure applications of cyclones, electrostatic precipitators, barrier filters (using fibre, felt and sintered filter elements) and various types of granular bed filters, are discussed in some detail and suggestions are made for the further research and development. The theory of capture mechanisms is reviewed in so far as relevant in the present context. Turbulent flow, electrostatic forces, and re-entrainment are the phenomena that require special attention in almost all applications.
In this paper my aim is to shed light on the common behaviour of human beings by looking at 'firs... more In this paper my aim is to shed light on the common behaviour of human beings by looking at 'first contacts': the situation where people with unshared histories first meet (who don't speak one an others' language, don't have access to interpreters, etc.). The limits of the human life form are given by what is similar in the common behaviour(s) of human beings. But what is similar should not be understood as something that is biologically or psychologically or transcendentally shared by all human beings. What is similar is what human beings would recognise as similar in first or other contacts-a similarity that is, in a way, transcendentally grounded, but the content of this grounding remains tied to the local situation of actual encounters. To be a human person, it is both an empirical and a transcendental precondition that one knows the certainties of particular form(s) of life and that one is capable of recognising and dealing with an indefinite variety of human behaviours. Because I participate in form(s) of life, I can interact with other form(s) of life. By considering first contacts and by interacting with other communities, one can learn to understand better what the common behaviour(s) of human beings is/are.
In this paper my aim is to shed light on the common behaviour of human beings by looking at 'firs... more In this paper my aim is to shed light on the common behaviour of human beings by looking at 'first contacts': the situation where people with unshared histories first meet (who don't speak one an others' language, don't have access to interpreters, etc.). The limits of the human life form are given by what is similar in the common behaviour(s) of human beings. But what is similar should not be understood as something that is biologically or psychologically or transcendentally shared by all human beings. What is similar is what human beings would recognise as similar in first or other contacts-a similarity that is, in a way, transcendentally grounded, but the content of this grounding remains tied to the local situation of actual encounters. To be a human person, it is both an empirical and a transcendental precondition that one knows the certainties of particular form(s) of life and that one is capable of recognising and dealing with an indefinite variety of human behaviours. Because I participate in form(s) of life, I can interact with other form(s) of life. By considering first contacts and by interacting with other communities, one can learn to understand better what the common behaviour(s) of human beings is/are.
In a recent issue of Dialectica Putnam asks us to consider a world with three individuals, x l r ... more In a recent issue of Dialectica Putnam asks us to consider a world with three individuals, x l r x2, x3 1. How many objects are there in this world? In World I ("Carnaps's world") there are three objects; in World 11 ("the Polish logician's world") there are seven objects, because in the latter World or by the Polish logician's Conceptual Scheme (CS), for every possible set of particulars there is an object which is their (mereological) sum. For the metaphysical realist only one of these worlds can be the real one. According to Putnam's internal realism questions of existence only arise after a CS has been chosen. In his view this example of two CS (two theories?) with different ontologies, which appear to be equally adequate in every way, provides a counter example to Davidson's claim that conceptual relativity is incoherent 2. Putnam's own position is that conceptual relativism means that in order to answer questions like "How many objects are there?", "DO sets exist?" or "Are points parts of space?", one must first know the chosen CS. This is the meaning of "internal" in his "internal realism". The meaning of "realism" is that, once a CS is chosen, the answers are as dependent on how things are as in the opinion of metaphysical realists. There is no way by which a culture can force answers to such ontological questions given a CS has been chosen. Hence, not only are we free to classify whales as fish or mammals according to a chosen theory (or a CS?), but also logical primitives, like objects and existence, have a multitude of different uses rather than one absolute meaning. In other words, the extensions of ".. . is an object" or ".. . exists" differ in different lan
Edelman's target article purports to be about veridical representations. I argue that it woul... more Edelman's target article purports to be about veridical representations. I argue that it would be a mistake to think it has much to do with veridicality as normally understood.
Chemistry and Physics: No Need for Metaphysical Glue J. van Brakel (KU Leuven) Events and Discour... more Chemistry and Physics: No Need for Metaphysical Glue J. van Brakel (KU Leuven) Events and Discourses Consider four discourses for speaking about water. 1. The human-centred (non-scientific) discourse concerning manifest features of the world, what Putnam (1975) called the stereotypical features of water. This discourse on the "stuff" water is not restricted to common sense. It may include sophisticated (Husserlian or Wittgensteinian) phenomenology. 2. Scientific discourse concerning macroscopic bodies of water, emerging from the manifest discourse; for example the event of boiling water. Here we encounter macroscopic (scientific) theories such as thermodynamics and hydrodynamics. 3. The scientific discourse surrounding the characteristic "molecule" found in water, H 2 O. I will refer to it as the molecular or microscopic discourse.
In this paper I present a historiography of the recent emergence of philosophy of chemistry. Spec... more In this paper I present a historiography of the recent emergence of philosophy of chemistry. Special attention is given to the interest in this domain in Eastern Europe before the collapse of the USSR. It is shown that the initial neglect of the philosophy of chemistry is due to the unanimous view in philosophy and philosophy of science that only
ABSTRACT. In this paper I present a historiography of the recent emergence of philosophy of chemi... more ABSTRACT. In this paper I present a historiography of the recent emergence of philosophy of chemistry. Special attention is given to the interest in this domain in Eastern Europe before the collapse of the USSR. It is shown that the initial neglect of the philosophy of chemistry is due to the unanimous view in philo-sophy and philosophy of science that only physics is a proper science (to put in Kant’s words). More recently, due to the common though incorrect assumption that chemistry can in principle be reduced to physics, the neglect continued, even when interest in sciences such as biology and psychology entered more strongly in philosophy of science. It is concluded that chemistry is an autonomous science and is perhaps a more ‘typical ’ science than physics. Kant said that there are in the world ‘two things which never cease to call for the admiration and reverence of man: the moral law within ourselves, and the stellar sky above us. ’ But when we turn our thoughts towards the ...
PSA: Proceedings of the Biennial Meeting of the Philosophy of Science Association
Recent discussions about the argument from design have taken into account developments in cosmolo... more Recent discussions about the argument from design have taken into account developments in cosmological theories, most especially the so-called anthropic principle associated with the "WheelerM-and "Carter"-universes.l Part of these discussions can perhaps be summarized as briefly as can be in the following opposition: 1. The world is very unusual, so it must have been made by an intelligent creator. 2. The world is very unusual, but unusual things do occur by chance. The phrase "the world is very unusual" is shorthand for something like: 3. It is extremely improbable that a random concatenation of the forces, energies, particles, fields of the universe (or whatever we think the building blocks are) should, in a single mal, form into anything orderly, let alone anything that supports our form of intelligent life. Reference is made in [3] to the status of the big-bang (as distinct from later events such as the emergence of life or consciousness); for by concentrating on that, the notion of chance events can be given concrete interpretation by referring to cosmological theories, in particular: a. Carter: All logically possible universes (of which there are infinitely many) actually co-exist. Anything remotely similar to a universe like ours is logically possible, but highly improbable. b. Wheeler: There exists a sequence of universes (without memory), each of them extremely improbable; we are in one of them. Both theories model possible outcomes of classical big-bang theory. Commenting on this particular discussion implies that I will start by leaving out the following aspects (each of which might outrule the relevance of the present discussion): i. Arguments purporting to show that our universe (or the emergence of life) is a unique event; considerations in terms of probabilities don't therefore apply to it.
Abstract In this communication, we report some data for the dewatering of a coal flotation concen... more Abstract In this communication, we report some data for the dewatering of a coal flotation concentrate in which very fine particles occur Dewatering is carried out by pressure filtration (up to 6 bar) followed by blowing to partially dry the cake (the filtration and dewatering phase respectively). For the systems studied, a reasonable prediction of the air consumption in either a lab filter, or a one-element test filter, or a full-scale continuous filter is possible, based on measurement of the liquid permeability for saturated flow in a lab filter cake. Together with scaling-up characteristics of the filtration step (not reported here), this gives the possibility of a reliable prediction of the required size and energy consumption of a large-scale continuous-pressure filter based on bench-scale test data.
Criteria for Selecting Appropriate Technologies Under Different Cultural, Technical and Social Conditions, 1980
The purpose of this paper is to illustrate by means of fifteen brief case studies the practical p... more The purpose of this paper is to illustrate by means of fifteen brief case studies the practical problems involved in assessing the appropriateness of production systems (be it before or after their introduction) and the institutional frameworks that are meant to aid in the construction of appropriate production systems. This constitutes the second and major part of the paper. In the first part a conceptual framework is presented, indicating some of the theoretical problems involved in assessing appropriateness.
Coal particles (1–8 mm) were subjected to size reduction tests under carefully controlled conditi... more Coal particles (1–8 mm) were subjected to size reduction tests under carefully controlled conditions (in particular single particle tests). It was found that in the primary breakage of these particles, only a few fragments are formed and the number of fragments formed does not seem to depend on the energy input. (This applies both to fracture and abrasion). These results suggest that coal breakage should be analyzed in terms of the number of breaking cycles, whereas the breakage (and the energy consumption) in any single cycle should be related to the micro structure of the coal particles.
Abstract This is a review of gas cleaning methods to be used for particulate removal from the gas... more Abstract This is a review of gas cleaning methods to be used for particulate removal from the gases emerging from pressurized coal gasifiers or fluid bed combustors at high temperature and high pressure. References are given (collected in tables) for the emissions of these processes, the inlet requirements if the hot gas is to pass a turbine and all cleaning methods that have been proposed in this context, including the removal of gaseous alkalis. The design feasibility and available performance data for high temperature, high pressure applications of cyclones, electrostatic precipitators, barrier filters (using fibre, felt and sintered filter elements) and various types of granular bed filters, are discussed in some detail and suggestions are made for the further research and development. The theory of capture mechanisms is reviewed in so far as relevant in the present context. Turbulent flow, electrostatic forces, and re-entrainment are the phenomena that require special attention in almost all applications.
Abstract This is a review of gas cleaning methods to be used for particulate removal from the gas... more Abstract This is a review of gas cleaning methods to be used for particulate removal from the gases emerging from pressurized coal gasifiers or fluid bed combustors at high temperature and high pressure. References are given (collected in tables) for the emissions of these processes, the inlet requirements if the hot gas is to pass a turbine and all cleaning methods that have been proposed in this context, including the removal of gaseous alkalis. The design feasibility and available performance data for high temperature, high pressure applications of cyclones, electrostatic precipitators, barrier filters (using fibre, felt and sintered filter elements) and various types of granular bed filters, are discussed in some detail and suggestions are made for the further research and development. The theory of capture mechanisms is reviewed in so far as relevant in the present context. Turbulent flow, electrostatic forces, and re-entrainment are the phenomena that require special attention in almost all applications.
Abstract This is a review of gas cleaning methods to be used for particulate removal from the gas... more Abstract This is a review of gas cleaning methods to be used for particulate removal from the gases emerging from pressurized coal gasifiers or fluid bed combustors at high temperature and high pressure. References are given (collected in tables) for the emissions of these processes, the inlet requirements if the hot gas is to pass a turbine and all cleaning methods that have been proposed in this context, including the removal of gaseous alkalis. The design feasibility and available performance data for high temperature, high pressure applications of cyclones, electrostatic precipitators, barrier filters (using fibre, felt and sintered filter elements) and various types of granular bed filters, are discussed in some detail and suggestions are made for the further research and development. The theory of capture mechanisms is reviewed in so far as relevant in the present context. Turbulent flow, electrostatic forces, and re-entrainment are the phenomena that require special attention in almost all applications.
Abstract This is a review of gas cleaning methods to be used for particulate removal from the gas... more Abstract This is a review of gas cleaning methods to be used for particulate removal from the gases emerging from pressurized coal gasifiers or fluid bed combustors at high temperature and high pressure. References are given (collected in tables) for the emissions of these processes, the inlet requirements if the hot gas is to pass a turbine and all cleaning methods that have been proposed in this context, including the removal of gaseous alkalis. The design feasibility and available performance data for high temperature, high pressure applications of cyclones, electrostatic precipitators, barrier filters (using fibre, felt and sintered filter elements) and various types of granular bed filters, are discussed in some detail and suggestions are made for the further research and development. The theory of capture mechanisms is reviewed in so far as relevant in the present context. Turbulent flow, electrostatic forces, and re-entrainment are the phenomena that require special attention in almost all applications.
In this paper my aim is to shed light on the common behaviour of human beings by looking at 'firs... more In this paper my aim is to shed light on the common behaviour of human beings by looking at 'first contacts': the situation where people with unshared histories first meet (who don't speak one an others' language, don't have access to interpreters, etc.). The limits of the human life form are given by what is similar in the common behaviour(s) of human beings. But what is similar should not be understood as something that is biologically or psychologically or transcendentally shared by all human beings. What is similar is what human beings would recognise as similar in first or other contacts-a similarity that is, in a way, transcendentally grounded, but the content of this grounding remains tied to the local situation of actual encounters. To be a human person, it is both an empirical and a transcendental precondition that one knows the certainties of particular form(s) of life and that one is capable of recognising and dealing with an indefinite variety of human behaviours. Because I participate in form(s) of life, I can interact with other form(s) of life. By considering first contacts and by interacting with other communities, one can learn to understand better what the common behaviour(s) of human beings is/are.
In this paper my aim is to shed light on the common behaviour of human beings by looking at 'firs... more In this paper my aim is to shed light on the common behaviour of human beings by looking at 'first contacts': the situation where people with unshared histories first meet (who don't speak one an others' language, don't have access to interpreters, etc.). The limits of the human life form are given by what is similar in the common behaviour(s) of human beings. But what is similar should not be understood as something that is biologically or psychologically or transcendentally shared by all human beings. What is similar is what human beings would recognise as similar in first or other contacts-a similarity that is, in a way, transcendentally grounded, but the content of this grounding remains tied to the local situation of actual encounters. To be a human person, it is both an empirical and a transcendental precondition that one knows the certainties of particular form(s) of life and that one is capable of recognising and dealing with an indefinite variety of human behaviours. Because I participate in form(s) of life, I can interact with other form(s) of life. By considering first contacts and by interacting with other communities, one can learn to understand better what the common behaviour(s) of human beings is/are.
In a recent issue of Dialectica Putnam asks us to consider a world with three individuals, x l r ... more In a recent issue of Dialectica Putnam asks us to consider a world with three individuals, x l r x2, x3 1. How many objects are there in this world? In World I ("Carnaps's world") there are three objects; in World 11 ("the Polish logician's world") there are seven objects, because in the latter World or by the Polish logician's Conceptual Scheme (CS), for every possible set of particulars there is an object which is their (mereological) sum. For the metaphysical realist only one of these worlds can be the real one. According to Putnam's internal realism questions of existence only arise after a CS has been chosen. In his view this example of two CS (two theories?) with different ontologies, which appear to be equally adequate in every way, provides a counter example to Davidson's claim that conceptual relativity is incoherent 2. Putnam's own position is that conceptual relativism means that in order to answer questions like "How many objects are there?", "DO sets exist?" or "Are points parts of space?", one must first know the chosen CS. This is the meaning of "internal" in his "internal realism". The meaning of "realism" is that, once a CS is chosen, the answers are as dependent on how things are as in the opinion of metaphysical realists. There is no way by which a culture can force answers to such ontological questions given a CS has been chosen. Hence, not only are we free to classify whales as fish or mammals according to a chosen theory (or a CS?), but also logical primitives, like objects and existence, have a multitude of different uses rather than one absolute meaning. In other words, the extensions of ".. . is an object" or ".. . exists" differ in different lan
Edelman's target article purports to be about veridical representations. I argue that it woul... more Edelman's target article purports to be about veridical representations. I argue that it would be a mistake to think it has much to do with veridicality as normally understood.
Chemistry and Physics: No Need for Metaphysical Glue J. van Brakel (KU Leuven) Events and Discour... more Chemistry and Physics: No Need for Metaphysical Glue J. van Brakel (KU Leuven) Events and Discourses Consider four discourses for speaking about water. 1. The human-centred (non-scientific) discourse concerning manifest features of the world, what Putnam (1975) called the stereotypical features of water. This discourse on the "stuff" water is not restricted to common sense. It may include sophisticated (Husserlian or Wittgensteinian) phenomenology. 2. Scientific discourse concerning macroscopic bodies of water, emerging from the manifest discourse; for example the event of boiling water. Here we encounter macroscopic (scientific) theories such as thermodynamics and hydrodynamics. 3. The scientific discourse surrounding the characteristic "molecule" found in water, H 2 O. I will refer to it as the molecular or microscopic discourse.
In this paper I present a historiography of the recent emergence of philosophy of chemistry. Spec... more In this paper I present a historiography of the recent emergence of philosophy of chemistry. Special attention is given to the interest in this domain in Eastern Europe before the collapse of the USSR. It is shown that the initial neglect of the philosophy of chemistry is due to the unanimous view in philosophy and philosophy of science that only
ABSTRACT. In this paper I present a historiography of the recent emergence of philosophy of chemi... more ABSTRACT. In this paper I present a historiography of the recent emergence of philosophy of chemistry. Special attention is given to the interest in this domain in Eastern Europe before the collapse of the USSR. It is shown that the initial neglect of the philosophy of chemistry is due to the unanimous view in philo-sophy and philosophy of science that only physics is a proper science (to put in Kant’s words). More recently, due to the common though incorrect assumption that chemistry can in principle be reduced to physics, the neglect continued, even when interest in sciences such as biology and psychology entered more strongly in philosophy of science. It is concluded that chemistry is an autonomous science and is perhaps a more ‘typical ’ science than physics. Kant said that there are in the world ‘two things which never cease to call for the admiration and reverence of man: the moral law within ourselves, and the stellar sky above us. ’ But when we turn our thoughts towards the ...
PSA: Proceedings of the Biennial Meeting of the Philosophy of Science Association
Recent discussions about the argument from design have taken into account developments in cosmolo... more Recent discussions about the argument from design have taken into account developments in cosmological theories, most especially the so-called anthropic principle associated with the "WheelerM-and "Carter"-universes.l Part of these discussions can perhaps be summarized as briefly as can be in the following opposition: 1. The world is very unusual, so it must have been made by an intelligent creator. 2. The world is very unusual, but unusual things do occur by chance. The phrase "the world is very unusual" is shorthand for something like: 3. It is extremely improbable that a random concatenation of the forces, energies, particles, fields of the universe (or whatever we think the building blocks are) should, in a single mal, form into anything orderly, let alone anything that supports our form of intelligent life. Reference is made in [3] to the status of the big-bang (as distinct from later events such as the emergence of life or consciousness); for by concentrating on that, the notion of chance events can be given concrete interpretation by referring to cosmological theories, in particular: a. Carter: All logically possible universes (of which there are infinitely many) actually co-exist. Anything remotely similar to a universe like ours is logically possible, but highly improbable. b. Wheeler: There exists a sequence of universes (without memory), each of them extremely improbable; we are in one of them. Both theories model possible outcomes of classical big-bang theory. Commenting on this particular discussion implies that I will start by leaving out the following aspects (each of which might outrule the relevance of the present discussion): i. Arguments purporting to show that our universe (or the emergence of life) is a unique event; considerations in terms of probabilities don't therefore apply to it.
Abstract In this communication, we report some data for the dewatering of a coal flotation concen... more Abstract In this communication, we report some data for the dewatering of a coal flotation concentrate in which very fine particles occur Dewatering is carried out by pressure filtration (up to 6 bar) followed by blowing to partially dry the cake (the filtration and dewatering phase respectively). For the systems studied, a reasonable prediction of the air consumption in either a lab filter, or a one-element test filter, or a full-scale continuous filter is possible, based on measurement of the liquid permeability for saturated flow in a lab filter cake. Together with scaling-up characteristics of the filtration step (not reported here), this gives the possibility of a reliable prediction of the required size and energy consumption of a large-scale continuous-pressure filter based on bench-scale test data.
Criteria for Selecting Appropriate Technologies Under Different Cultural, Technical and Social Conditions, 1980
The purpose of this paper is to illustrate by means of fifteen brief case studies the practical p... more The purpose of this paper is to illustrate by means of fifteen brief case studies the practical problems involved in assessing the appropriateness of production systems (be it before or after their introduction) and the institutional frameworks that are meant to aid in the construction of appropriate production systems. This constitutes the second and major part of the paper. In the first part a conceptual framework is presented, indicating some of the theoretical problems involved in assessing appropriateness.
Coal particles (1–8 mm) were subjected to size reduction tests under carefully controlled conditi... more Coal particles (1–8 mm) were subjected to size reduction tests under carefully controlled conditions (in particular single particle tests). It was found that in the primary breakage of these particles, only a few fragments are formed and the number of fragments formed does not seem to depend on the energy input. (This applies both to fracture and abrasion). These results suggest that coal breakage should be analyzed in terms of the number of breaking cycles, whereas the breakage (and the energy consumption) in any single cycle should be related to the micro structure of the coal particles.
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